Here's the shop manual specification for the 'local manufacture' tool
(adobe file at the bottom) Basically, it's just a long bar with a hook that you hold on the front of the riser, the pivot point, and pull the spring back using the mechanical advantage of the leverage from the bar.
I made mine from some scrap 1/4" X 1" flat bar stock (pic from the old thread). I cut the main bar 2ft long, and drilled 2 holes, one at the bottom/end, and another 3 1/2" from the end. I cut the second piece 8 1/2" long, with a hole drilled in the end of it, and 3 holes at the other end.
I used a 3" bolt into the end hole of the long bar to make a 'T' at the bottom so the bar won't twist as it rests against the riser. This is like the welded pipe in the shop manual drawing. The hole 3 1/2" up this bar is used to attach the second piece, using a bolt and nut. This is like the long hook in the drawing. The 3 other holes were for adjustment to position the 'S' hook that I used to attach the tool to the spring.
I think almost any piece of stock, even pipe, could be used to make the long lever, and the hook could be as simple as a piece of heavy wire or even cable, but I'd use something very heavy duty to make certain the spring doesn't come off while stretched!
